Automatic slack adjuster for vehicle brakes, especially railway car brakes



June 11, 1940.

B. H. BROWALL In M. 2,203,890 AUTOMATIC SLACK ADJUSTER FOR VEHICLE BRAKES,

ESPECIALLY RAILWAY CAR BRAKES Filed July 13, 1937 4 Sheets-Sheet 1 flaw 1710/.

a dwww/ June 11, 1940.

B. H. BROWALL ET AL 0 AUTOMATIC SLACK ADJUSTER FOR VEHICLE BRAKES,

ESPECIALLY RAILWAY CAR BRAKES Filed July 13, 1957 4 Sheets-Shee t 2 2H l7 IO IH 28 H 25 .3 Fae-.3

4 III n. In

B. H. BROWALL ET AL 2,203,890 SLACK ADJUST FOR VEHICLE BRAKES,

4 Sheets-Sheet 5 'June 11, 1940.

B. H. BROWALL El AL 2,203,890 AUTOMATIC SLACK ADJUSTER FOR VEHICLE BRAKES,

ESPECIALLY RAILWAY CAR BRAKES Filed July 13, 1937 N2 VIII/l a v/ I 4 Sheets-Sheet 4' Patented' June 11, 1940 UNITED STATES AUTOMATIC PATENT OFF 2,203,89 ICE HICLE. BRAKES, .ESPECIALLY RAILWAY CAR BRAKES Bert Henry BroWaILMalmo, Sweden, and Ludwig Scheib, Kaiserslautern, Germany, assignors to Svenska- Aktiebolaget Bromsregulator, Malmo, Sweden, a corporation of Sweden Application July 13, 1937, Serial No. 153,414 r In Austria April 7, 1937 a 15 Claims. (01. 188-202) This invention relates to iautomatic slack ad justers for vehicle brakes, especially railway car brakes, and more particularly to such automatic slackadjusters which are operative not only for reducing too large a slack or clearance between the brake shoes and the wheels but also for increasing the slack or clearance therebetween,

when too small, and whichperform their slack increasing movement under the action of the stresses arising too early in Ithebrake rigging at a braking operation. Automatic slack adjusters of this double-acting type havemany impor- \tant advantagesbut also. the drawback that they can perform an undesirable slack. increasing movement under the action of stresses other than those arising ata braking operation; for instance such sudden stresses which atreleased brake may arisein thelbrake rigging duertozshocks and the.

like when switching the cars. Certainly, in order to avoid such undesiredslack increasing movement it is already known toconstructthe slack adjusters and their actuating. devices in such. a

consequently, will come to a standstill in aposiway that the slack adjuster is locked against slack increasing movement not only during the application of the brake, namelywhen thefibrake piston has travelled the distancefcorresponding to the desired brakeshoe clearance, but also at the release of the brake, namely when the brake piston has reached itsnorrnalend position corresponding to fully releasedl brake. Under'cerr tain circumstances this known precaution, how-.- ever, is not satisfactory because it may happen that the various parts of the brakefor one reason orthe other, for instance due toahand brake that has not beenrfully released, will be prevented from returning to their normal end positioncorresponding to fullymeleasedbrake and,

jltion in which the intendedlocking of the slack adjuster against slack increasing movement has not yet taken place. i i H a The object -of the invention is, to improve automaticslack adjusters of the double-acting adjuster of the screw type with a locking device 3 which only performs thefunction proposed by the invention. H 3

Figsa am a xialesec i n a d a r ss t o substant all enih- IVTIY. Bis-,3,

respectively, of a modified form of a doubleacting slack adjuster of the screw type, .in which the locking device also performs the further function of locking the slack adjuster against further slack increasing movement at the application of the brake when the brake piston has travelled the distance corresponding to the desired brake shoe clearance.

Fig. 5 is an axial section of a double-acting slack adjusterof the toothed rod type, in which the locking device performs the same further function as in the form of Figs. 3 and 4.

Figs. 6 and '7 are a side view, partlyin section, and a cross section substantially on the line VIIVII in Fig. 6, respectively, of a double-acting slack adjuster of the screw type, in which the locking device besides ofthe function proposed by the invention also performs the further function of transmitting the slack reducing movement from the actuating device of the slack adjuster to the slack adjustingnut thereof at; the release of the brake. ;Figs. 8, 9 and 10 are an axial section and cross sections on lines IXIX and X--X in Fig. 8, respectively, of a double-acting slack adjuster of the screw type, in which the locking device besides of the function proposed by the invention also performs both the aforesaid further functions, namely the function of locking the slack adjuster against further slack increasing move- Yment when the brake piston at an application of the brake has travelled the distance corresponding to the desired brake shoe clearance, and the function of transmittingthe slack reducing movement from the actuating device of the slack adjuster to the slack adjusting nut thereof at the release of the brake;

Fig. 11 is a diagrammatic view illustrating, by

way of example, howa double-acting slack adjuster of the screw type and the actuating device thereof may be mounted in the brake rigging.

The most well known double-acting slack adjusters of thescrew type. comprise a two-part rod forming part of the brakerigging, the two parts of saidrod being connected by a non-selflocking screw connection comprising a screw and a nut, one of which, usually the screw, is non.- rotatable and the other of which,usuallythe nut, is rotatable for adjusting the effective length of the rod and, as a resulthereof, the slack or brake shoe clearance. The construction is such that under the control of an actuating device which in turn is operated by the application and release movements of the brake, the rotatable partof ,the non-selflocking screw connection at an application of the brake is locked against rotation in the direction of an increase of the brake shoe clearance when the brake piston has travelled,

the distance corresponding to the desired brake shoe .qlea a sa and at the re ease. 9 habra s engagement with the ratchet wheel 13.

is rotated in the direction of a reduction of the brake shoe clearance for the purpose of reducing the brake piston stroke to its normal value if this, on account of too large a brake shoe clear" purpose of transmitting the braking power from the brake actuator comprising the brake cylinder 4 and the brake piston 5 to the. brake shdes 6. The nut I and a sleeve l to which the nut is.

secured can, by the operation of the slack adjuster, be locked against rotation relatively to a non-rotatable part 9 which usually is formed with an eye for the attachment of the two-part rod to the lever 3. This operation .of the slack adjuster is obtained by rotating a rotatable casing Ill forming part of the slack adjuster in one direction or the other. The rotation of the casing I is effected in dependence upon the application and release movements of the brake by means of an actuating device acting upon a crank arm I I provided on the casing It. Through this actuating device indicated at I2 the casing I8 is rotated in opposite directions at the application and the release of the brake.

The form of the slack adjuster shown in Figs. 1 and 2 in all essentials is well known in the art (compare for instance Fig. 4 of the U. S. Patent No.'l,983,897) only excepting the locking device proposed by the invention and, therefore, will be described only to the extent necessary for explaining the construction and operation of said lockingdevice. This comprises a ratchet wheel I3 secured on the rotatable sleeve "I, and a pawl I i ooacting with the ratchet wheel. This pawl "I4 is pivoted on a pin' I5 .in an opening 26 in the side of asleeve I'i which in a known man: ner is secured on the non-rotatable part 9 and provided with a guiding screw thread I8 cooperating with a corresponding guiding screw thread I9 in the casing III. The cooperating threads I8, I9 serve the known purpose of allowinga thrust ring 20 secured on the sleeve I to engage a thrust surface 2| on the rotatable sleeve I! when at the application of the brake the casing Ill has been rotated through a certain angle in the direction of the arrow A in Fig. .2 and the brake piston has travelled the distance corresponding to the desired value of the brake shoe clearance. As soon as this has taken place the arising brak ing power is transmitted from the non-rotatable part 9 directly through the thrust surface 2| to the thrust ring 20 and therefrom through the sleeve I and the nut I to the screw threaded rod part 2. The friction arising between the ring 20 and the surface 2| due to the thrust pressure locks the sleeve 7 and, consequently, the nut "I against rotation. As soon as the casing til at the application of the brake begins to rotate in the direction of the arrow A in Fig. 2, the pawl I4, by means of a spring pressed friction shoe 22 mounted on the pawl and cooperating with the inside of the rotatable casing II], is moved. out of. Through the cooperation of the friction shoe 22 with the casing ID the pawl I4 is held out of engagement with the ratchet wheel I3 until the casing II) at the release of the brake is again rotated in the reverse direction, that is in the direction of the R in Fig.2 begins, the pawl I4 is again moved, through the cooperation of the friction shoe 22 with the rotatable casing IE! and, if desired, by

the aid of a spring 23, in engagement with the The pawl I4 remains in this ratchet wheel I3.

engaged position until the casing I0 at a new ap plication of the brake is again rotated in the direction of the arrow A in Fig. 2. Thus, the pawl It will be held'outof engagement with the ratchet nut I connected thereto in the direction'of an increase of the brake shoe clearance. Thus, the slack adjuster at released brake, irrespective of the position in which the release movement of the brake may have come to astandstill, always will be locked against slack increasing movement, so

that an increase of the slack or brakeshoe clearance under the action of switching shocks or the like cannotv take place.

In the modified form illustrated in Figs. 3 and 4 the locking device l3, l4 performs not only the function proposed by the invention, namely that of locking the slack adjuster against slack increasing (screwing out) movement during the whole release movement of the brake and until the brake is applied anew, but also the further function of locking the slack adjusten against furth'er slack increasing (screwing out) movement when at the application of the :brake the brake piston has travelled the distance corresponding to the desired value of the brake shoe Sclearance, that is the same function which in the form of Figs. 1 and 2 is performed by the cooperating guiding threads I8, I9 and the friction device '20, 2|. To this end in the form of Figs. 3 and 4 there is provided in the inside of the rotatable casing ID a recess or groove 24. In the same manner as in the form of Figs. 1 and 2 the pawl I4 is moved out of engagement with the ratchet wheel I3 through the rotation of'the casing I0 in the direction of the arrow A (Fig. 4) at the application of the brake. When the brake piston, however, has

I travelled a certain distance corresponding to the with the ratchet wheel I3 by the spring 23 and locks the sleeve 1 carrying the slack adjusting nut I of the non-selflockin'g screiw connection I, '2 (compare Fig. 11) against rotation in the slack increasingdirection. The pawl I4 remains engaged with the ratchet wheel I3 also during the release of the brake and until the brake is applied again, sothat the slack adjuster after-each braking operation, irrespective of the position in which the brake release movement may have come to a standstill, will be locked against screwing out movement, that is slack increasing movement, under the action of switching shocks and the like.

In the form of Figs. 3 and 4 rotation of the sleeve 1 and the nut I attached thereto in the direction of a screwing in, that is a slack reducing movement is effected by means of a pawl 25 mounted in the rotatable casing I0 and cooperating with a rotatable ratchet wheel 2-65 which is connected with the sleeve 1 by means of a friction clutch 21 compressed by a springu30. When at the application. ofthe brake the brake rigging is stressed the compression of the friction clutch 21, however is relieved so that a slack increasing movement can take place when the pawl I4 is out of engagement. a

I The form of a double-acting slack adjuster of the toothed rod type illustrated'in Fig. 5 is well known in the art (compare :17. S. Patent No..

they take when the brake is released. At the application of1the brake the housing 33 of the slackadjuster in a known manner moves in the direction of the arrow A in relation to the actuating rod 3| until the ear 36.on the housing 33 abuts the actuating abutment 31., Immediately at the commencement of this movement I the lever 35 on accountof its cooperation with the teeth 32 is turned in a clockwise direction as viewed in the figure, whereby the sleeve,34 is displaced to the right and pushes the expandable main pawl nut 38. (which is divided into a plurality of resiliently connected sectors) away from its conicalseat39in the rod part .4llas a long as the latter and the housing 33 under the action of the spring 4| take the position in rela I tion to each other, which is shown on the drawings. Now the pawl nut38 in a known manner can permit a sliding movement of the rod part 43 (which is provided with teeth in the form era screw thread for cooperation with the two. pawlnuts 38 and 42) relatively ,to the rod part 40 in the direction of an increaseof the brake shoe clearance. .After. the lever 35, at the beginning of the application movement of, the

brake, having been turned to the limit in the clockwise direction it slides, at the continued movement of the housing 33 in relation to the rod 3|, over the teeth 32, this sliding of the lever 35 over the teeth 32 being rendered possible by such an arrangement of the rod 3I that it can yield sideways against the action of a displacement relatively to the rod part 40 in th slack increasingdirection. I

When the brake is released therod part 40 under the action of'the spring 4| again abuts the I abutment 33a. for the same in the housing 3.3,

and then the housing33 moves in the direction of the arrow R in relation to the actuating rod 3I. 35 through its cooperation with the teeth 32. on

the rod 3|. is turnedin thecounter-clockwise,

direction, whereby the sleeve. 34 is displaced away from the pawl nut 38 and allows the latter to seat itself and to remain seated in the conical seat 39 during the whole release movement-of- In Fig. 5' the parts "of theslack adjuster are shown in the position which tation betweenthe two sleeves .I and As soon as this movement beginsthe lever when sozseated the pawl nut 38 looks the rod thefbrake land until the brakel is applied anew.

40 againstiidisplacement relatively to the rod 43 in theslack increasing direction. Thelever 35,

havingbeen turnedtothelimit in the counter clockwise direction immediately at the beginning of the release movement of the brake, will slideflovertthe teeth32 at the continued brake release movement in the same manner as at the application movement of the brake. As will be readily understood from the. foregoing description the sla'ckadjuster after each braking operation irrespective of the position in which the brakerelease movement may have come to a I standstill, Willi beilocked against slack increasing movement due like. 2 I I. i Inthe form of a double-acting slack adjuster of the screw type illustrated in Figs. 6 and '7 the crankarm II by which the rotatable casing III of the slack adjuster is connected to the actuating device I2 is pivoted by means of a pin 5|] parallel to; the, axis of the casing I0 in'a side opening to switching shocks and the therein, 1which opening preferably is surrounded bya flange 5| or the, like. Inside of the casing III the arm II which is movable within limits around 'its pivot .pin 50,.isprovided with a detent 52 cooperatinggwith a ratchet wheel 53 se cured on the sleeve 1 carrying the nut I of the non-selflocking screw-connection I, 2. The detent 52 is actuated by a spring 54 which tends to move I the detent in engagement with the ratchetwheel 53. When at the application of the brake the arm II isactuated by the actuating device I2 compare Fig. 11) in the direction of the arrow A in Fig. 7, first the arm II is turned about its pivot pin 50 so that thedetent 52 is moved out of engagement with the ratchet wheel 53. Then the rotatable casing I0 is rotated around its axis in the direction of the arrow A in Fig. 7, and due to this rotation of the casing I0 the coacting guide threads I8 and I 9 on the nonrotatable sleeve I1 and the casing I 0 allow the thrust ring 2|] (which is supported against the casing II] by means of a thrust ball bearing 55) to go. into locking engagement, with the thrust surface 2|,when the brake piston has travelled the distance corresponding to the desired value of the brakeshoe. clearance. By this locking engagement the sleeve. I is locked against rotation in the slack increasing direction. In order to secure a greater frictional resistance against ro- II than betweenthe casing: I I1 and the sleeve I during the application of the brake before the thrust ring 20 has come in engagement with the thrust surface 2I,,so that the sleeve 1 does not partake in the rotation of the casing I0 but only rotates under the actionflof stresses arising too early (that is before thebrake piston has travelled the distance corresponding to the desired brake shoe like .frictionally engaging the inside of the sleeve I'I. When at the release of the brake the arm II is actuated by the actuating device I2 in the direction of the arrow B in Fig. 7, first the arm I I is turned aboutthe pin 50 so that the detent I .52 is moved in engagement with the ratchet direction ofithe arrow.. R.the casing .IOand, on

account of the engagement of the. detent 52 in the ratchet wheel 53, the latter and the sleeve 1 and the nut I are rotated in the slack reducing direction. The .detent 52 remains in engagement with the ratchet wheel 53 and locks the slack adjuster against slack increasing movement irrespective of the position in which the release movement of the brake may come to a standstill, the detent being moved out of the said engagement only at the beginning of a new application of the brake. Thus, the .slack adjuster after each braking operation will be hooked against slack increasing movement under the action of switching shocks and the like irrespective of the position in which the brake may have come to standstill at the release of the same. At every release of the brake the slack adjuster performs a slack reducing movement, even though the slack clearance maybe proper. Because of the fact, however, that any too large reduction of the slack clearance will be automatically compensated by a corresponding slack increasing movement of the slack adjuster at the next application of the brake, the difference between the actual slack clearance at released brake and the slack clearance corresponding to the desired length of the brake piston stroke never will reach any harmful value.

In the form of a double-acting slack adjuster of the screw type illustrated in Figs. 8 to 10 the non-rotatable part provided with the attach ing eye 9 is constructed as a surrounding casing 66 in which a thrust ring 6| secured on the sleeve I carrying the nut of the non-selflocking screw connection I, 2 (compare Fig. 11) is rotatably arranged between two thrust faces 62 and 63 and supported by'a thrust ball bearing 64 and a spring 65 which normally holds the thrust ring 6| pressed against the-thrust surface 62. The arm II to which the actuating device I2 is connected issecured on a spindle 66 -rotatably but not slidably mounted in the casing I9 axially thereof, the arm II-projecting through a long slot 66a in the casing 66 and being rotatable relative thereto. The spind1e66 is provided with a guiding screw thread fi'l'cooperating with a corresponding internal thread in the bore of a ratchet disk GBrnounted on the spindle. The pitch of the said cooperating threads on the spindle 66 and the ratchet disk .68 is so large that the threads are non-selflocking. On =the side facing the thrust ring 6I the disk 6811s. provided with ratchet teeth 69 cooperating with corresponding ratchet teeth on the thrust ring 6|. The ratchet disk 68 also carries a radially slidable, spring pressed detent 16. for cooperation with ratchet teeth II inside of the casing 66. The teeth II are not arranged all around the inner circumference of the casing 60, the circumferential row of teeth 'II having an interruption or cutout portion as shown at I2. Preferably the teeth II are cut in the inside of a ring I3 so mounted in an annular groove in the-inside of the casing 66 that the ring can be adjusted angularly and set in adjusted position by means of a set screw I4,

Fig. 10. A spring I5 which is weaker than the spring 65 tends to press the disk'68 towards the because of being prevented therefrom by the en gagement of the detent 70 in the ratchet teeth II. Thus, due tov the cooperating guiding threads on the spindle and thematchetdisk, the latter is axially displaced against the action of the spring I5 until the detent 70 comes at the side of the ring I3 and, consequently, loses its engagement with the teeth II. When this occurs also the ratchet teeth 69 of the disk 68 are out of engagement with the corresponding ratchet teeth on the thrust'ring 6|. The disk 68, therefore, now partakes in the rotation of the spindle 66 until the detent l0 reachesthe cut out portion 72 of the ring 73. Then the disk 68 under the action of the spring 15 (which may be a compression spring or a torque spring or a combined compression and torque spring tending to displace or screw the disk 68 towards the thrust ring SI) moves on the guiding thread 61 on the spindle 66 towards the thrust ring GI and comes with its ratchet teeth 69 in engagement with the corresponding teeth on the thrust ring 6| and locks the latter and thereby the sleeve I against rotation in the slack increasing direction. This position in which the, parts are shown-in the drawings is arrived at when the brake piston has travelled the distance corresponding to the desired brake shoe clearance; Before arrival at this position, should the brake shoes already have been applied against the wheels and, as a result hereof, sufiicientstresses already have arisen in the brake rigging, a slack increasing (screwing out) movement takes place, the spring 65 being compressed a little due to the said stresses, so that the thrust ring 61 is deprived of its frictional contact with the thrustsurface 62 and will rest only against the thrust ball bearing 64, whereby the thrust ring 6| and thereby the sleeve 1 and the nut I of the non-selflocking screw connection I, 2 become free to rotate under the action of the said stresses in the brake rigging. At the increasing direction until the aforesaid position shown on the drawings is'arrived at, in which the ratchet teeth 69 again engage the corresponding ratchet teeth on the thrust ring 6| and stop further rotation in the slack increasing direction. At the release of the brake, during which the spindle 66 is rotated in the direction of the arrow R inFig. 10, the disk 68 remains with its ratchet teeth 69 in engagement with the corresponding ratchet teeth onthe thrust ring BI and rotates the latter and the sleeve 1 in the slack reducing direction, while the detent I6 slides backwards over the teeth II. Thus, after each braking operation the teeth 69 onthe disk 66 will be in engagement with the corresponding teeth on the thrust ring BI, and the detent III will be in engagement with the teeth II, irrespective of the position in which the brake at the release thereof may have come to a standstill, so that the slack adjuster as soon as the brake is released, will be locked. against slack increasing move ment under the action'of switching shocks and the like. 7

' I What weclaim and desire to secure by Letters Batentis:

ating rod, the feature that the said connecting 1. Inan automatic slack adjuster for'vehicle brakeaespecially railway car brakes, of the character describedimembers relatively movable for forth and back by the application and release movements of thebrake, respectively, for so controlling said locking device that it is; rendered active by acommencing movement of the actuating device in the release direction and inactive adjusting the 5 slack a locking device for locking said membersagainst slack increasing move,

ment in relation toeachother, and means including an actuating device adapted to .be moved by a commencing movement of the actuating device in the brake application direction, the locking device being so arranged that it also is operative for transmitting, at the release of the brake, amovement fromthe actuating device to one of said members in, relation to the other in the slack reducing direction.

2. In an automatic slack adjuster for vehicle brakes, especially railway car brakes, of the character described and of the type comprising a two-part non-self-lockingscrew connection one part of which is rotatable relatively to the other for adjusting the slack, a non-rotatable part, a rotatable casing, and an actuating device for rotating said casingforthand back at the application and the release of the brake, respectively, I

a ratchet wheel securely connected to the rotatablegpart of the non-selflocking screw connec-,

tion, and apawl cooperating with said ratchet Wheel, said pawl being pivotally mounted on said non-rotatable part of the slack adjuster and so frictionally engaged with the rotatable casing that the pawl is moved in engagement with the ratchet wheel and thereby locks the rotatable part of the non-selflocking screw connection able casing is provided with a recess or the like due to which thepawl at the rotation of the rotatable casing in the forward direction at the application. of the brake and in a position thereof corresponding to the desired value of the slack losesits frictional engagement with therotatable casing and as a result thereof engages itself with the ratchet wheel and thereby locks the I rotatable part of the non-selflocking screwcon nectionagainst slack increasing movement.

4:. In an automatic slack adjusterof the character described and of the type comprising, two

relatively slidable mamas one of which is provided with ratchet teeth and the other of which is provided with a pawl cooperating with the teeth of the first rod part and, when abutting a seat, locking the rod parts against slack. increasing movement in relation to each other, a housing, an abutment member movable in said housing towards and away from the pawl for unseating and seating the same, anactuating device including an actuatingrod adapted to perform a forward and abackward movement relatively to the housing at the application and the release of the brake, respectively, and a movable member mounted on the housing and operatively connecting the said abutment member to said actu- ,member and the said actuating rod are arranged .to cooperate in such a manner that at a commencing movement of the housing of the slack adjuster in, the brake release direction relatively ;to theactuating rodthe connecting member is actuatedby the actuating rod so as to move the movable abutment member away from the pawl for. allowing: the latter to seatitself, while at thecontinued movement of the housing in the brake release direction relatively to the actuating rod the latter slides relatively to the connecting'member, so that the latter only at a commencing movement of the housing in the brake application direction relatively to the actuating rod is again actuated thereby so as to move the movable abutment member towards the pawl for pushing it oif from its seat.

. 5, In an automatic slack adjuster of the char- 'acter described and of the type comprising a twopart non-selflocking screw connection one part of which is rotatable relatively to the other for adjusting the slack, a rotatable casing, an actuating device adapted to rotate said casing forth andback at the application and the release of the brake, respectively, and a driving connection between therotatable casing and the rotatable part of the non-selflocking screw connection for rotating said part in the slack reducing direction at the release of the brake, the feature that the said driving connection comprises a ratchet wheel securely connected to the rotatable part of the nonv elflocking screw connection, an arm operatively connected to the actuating device and pivotally mounted on the rotatable casing sothat the arm is movable withinlimits about an axis substantially parallel to the axis of the casing, and a detentcarried on said arm'and adapted to cooperate with the said ratchet wheelin'a manner so that the detent by a commencing movement of the actuating device in the direction in which it is moved at the release of the brake is engaged with the ratchet wheel on account of the arm, before it begins to carry with it the rotatalole casing, being turned about its pivotal axis,

the detent when engaged with the ratchet wheel locking the latter and thereby the rotatable part of the non-s'elflocking screw connection against rotation in the slack increasing direction, and the detent when engaged being" again disengaged from the ratchet wheel only by a commencing movement of the actuating device in the direction in which it is moved at the application of the brake.

j 6. In an automatic slack adjuster as claimed in claim 5 the additional feature that the rotatable part of the non-selflocking screw connection is, provided with a friction means cooperat ing with a non-rotatable part of the slack adjustor so as to ensure a greater frictional resistance,

against, rotation between the rotatable part of the non-selflocking screw connection and the said non-rotatable part of the slack adjuster than between the rotatable part, of the non-selflocking screw connection and the rotatable casing.

'7. In anautomatic slack adjuster for vehicle brakes, especially railway car brakjes, of the character described, a locking device for locking the slack adjuster against slack increasing movement,

spring means tending to keep said locking device in locking position, an actuating device adapted to be moved forth andback by the application and release movements of the brake, respectively, and controlling means operatively connected to said actuating device for transmitting a commencingmovement of the same, when applying Ithe'brake, to the locking device for releasing.

the latter against the action of the spring means, said controlling means being adapted to be effective for releasing the locking device up to a predetermined position only of the brake, corresponding to the desired value of the slack.

,8. In an automatic slack adjuster forvehicle brakes, especially railway car brakes, of the character described, a locking device for locking the slack adjuster against slack increasing movement, spring means tending to keep said locking device in locking position, an actuating device adapted to be moved forth and back by the application and release movements of the brake, respectively, and controlling means operatively connected to said actuating device for transmitting a commencing movement of the same in either direction to the locking device, so as to put said locking device out of action against the action .of the spring means at a commencingapplication movement and into action at a commencing release movement of the brake, said controlling means being adapted to be efi'ective for releasing the locking device up to a predetermined position only of the brake corresponding to the desired value of the slack.

9. In an automatic slack adjuster for brakes, especially railway car brakes, of the character described, a locking device for locking the slack adjuster against slack increasing movement, an actuating device adapted to be moved forth and back at application and release of the brake, respectively, and means operatively connected to said actuating device for setting said locking 'de-- 'vice into action when the brake, after having perform'eda movement inthe direction for applyingit, begins a movement in the direction for releasing. it, and for setting said. locking device out of action when the brake, after having performed a movement in the direction for releas ing it, begins a movement in the direction for applying it.

'10. In an automatic slack adjuster for vehicle brakes, especially railway car brakes, of the character described, a locking device for locking the slack adjuster against slack increasing movement, an actuating-device adapted to be moved forth and back by 'the'application and release movements of the brake, respectively, and means operatively connected to said actuating device for controlling said locking device in dependence upon the directions of the movements of the brake, so that said locking device is set into action when after cease of a movement of the brake in the direction for applying it, a movement of the brake in the direction for releasing it be- "gins, and so that said locking device is set out of action when after cease of a movement of the brake in the direction for releasing it, a movement of the brake in the direction for applying it begins.

11. In an automatic slack adjuster for vehicle.

upon the directions' of the movements of the brake "so that, with the brake in any given position, said locking device is in or out of action according to whether the brake arrived at such position on movement in the direction for releasing it or on movement in the direction for applying it. i r

'12. In an automatic slack-adjuster for vehicle brakes, especially railway car brakes, of the character described, a' locking device for locking the slack adjuster against slack increasing movement, an actuating device adapted to be moved forth and back by the application and release movements of the brake, respectively, and means operatively connected to said actuating device frictionally connected to said actuating device for transmitting a commencing movement thereof in either direction to'the locking device, so as to put said locking device out of action at a commencing application movement and into action at a commencing release movement of the brake. y

14. In an automatic slack adjuster for vehicle brakes, especially railway car brakes, of the character described, a locking device for locking the slack adjuster against slack increasing movement, an actuating device adapted to be moved forth and back by the application and release movements of the brake, respectively, and means slidably connected to said actuating device "for transmitting a commencing movement thereof in either direction to the locking device, so as to put said locking device out of action at a commencing application movement and into action at a commencing release movement of the brake.

'15. In an automatic slack adjuster for vehicle brakes, especially railway brakes, of the character described, a two-part brake rod one part of which is adapted to be displaced axially in relation to the other for taking up and letting out slack, an actuating device adapted to be moved forth and back by the application and release movements of the brake, respectively. a locking device in the form of a disengageable one-way clutch interposed between said actuating device and said rod part and adapted to couple said rod part to said actuating device at the release movement of the brake, and means operable by lost motion between said actuating device and said rod part for engaging said clutch when such lost motioncorresponds to a commencing movement of the brake in the di rection for releasing it, and for disengaging said clutch when such lost motion corresponds to a commencing movement of the brake in the direction for applying it.

BERT HENRY BROWALL.

LUDWIG SCHEIB. 

